Question

I’m trying to solve a part of my program, which has a #define new. Everything works well, until I try to create a class template that overrides the new operator, when I get the errors:

C:\Define_New_problem\main.cpp:18: error: expected type-specifier before 'dPushMemManFileLine'
C:\Define_New_problem\main.cpp:18: error: expected ';' before 'dPushMemManFileLine'
C:\Define_New_problem\main.cpp:21: error: expected ';' before '}' token
Process terminated with status 1 (0 minutes, 0 seconds)

Using MinGW. The (simplified) code is as follows:

#include <iostream>

#define new dPushMemManFileLine( __FILE__, __LINE__ ) ? 0 : new

using namespace std;

static const int NUM_NEW_STACK_SIZE = 256;
static struct { const char* filename; unsigned int line; } g_NewStackMemDebug[NUM_NEW_STACK_SIZE];
static int g_CurStack = -1;

template <class T>
class mypair {
  private:
    int a, b;
  public:
    mypair (int first, int second)
      {a=first; b=second;}
    static void* operator new(size_t size)
    {
    }
};

int dPushMemManFileLine( const char* filename, unsigned int line )
{
    if(g_CurStack >= NUM_NEW_STACK_SIZE )
        return 0;

    g_CurStack++;
    g_NewStackMemDebug[g_CurStack].filename = filename;
    g_NewStackMemDebug[g_CurStack].line = line;

    return 0; // needed for the new passthrough trick

}

int main()
{
    cout << "Hello world!" << endl;
    return 0;
}

Has anyone a good idea on how do I solve this problem?

Answer 1

Don’t.Ever.#define.Keywords.

Please, just don’t. It only makes problem. A #define replaces all occurences of the defined word with what you define it to be, so after the #define‘d new gets expanded, the operator overload looks like the following:

static void* operator dPushMemManFileLine( __FILE__, __LINE__ ) ? 0 : new(size_t size)
    {
    }

Uuups….
Then of course the question remains, why did you do that?